In general, there are two different types of door hinges, one type is the door can be opened and closed hinged by one side the other type is the door is opened and closed upper and lower side hinged by an upper side, i.e., a side closing type door and a top closing type door.
In the meantime, the latter is used for the door of a gas oven range or a microwave oven for home appliance. It shows in FIG. 1 in which the conventional composition of the door hinge is attached.
As shown in FIG. 1, a conventional door hinge 250 may include a fixing unit 210 installed at the door frame 100, an actuating unit 212 installed at the door 200 and hinge connected by the hinge 226 to the fixing unit 210 and rotatably move around the hinge 226, thereby opening or closing the door.
In the meantime, a guide unit 214 is accommodated between the actuating unit 212 and the fixing unit 210 and guides open and close operation of the door 200.
The guide unit 214 may include a connection plate 216 installed at the fixing unit 210, a rotary motion plate 220 rotatably moving around a pin 218 by connecting to the connection plate 216 by the pin 218, and a guide pin 224 connected to an end of the rotary motion plate 220 and moves up/down along with guide holes 222 which are formed in both sides of the actuating unit 212.
If the guide unit 214 rotate the actuating unit 212, the guide pin 224 vertically move along with the guide hole 222 and simultaneously the rotary motion plate 220 connected to the guide pin 224 rotatably move around the pin 218 according to the movement of the guide pin 224. Therefore, the door 200 steadily performs an opening operation.
In the meantime, the above-described door hinge further may include a spring, the spring may have a function of reducing rotation speed of the door so that the door is closed slowly by generating a compressive force in a door closing start stage.
However, the compressive force of the spring has limited to support a door load with only one spring, there is a disadvantage in that it is impossible to efficiently generate a larger compression force to support the door load when closing of the door is continuously made. Thus the rotational speed of the door cannot be effectively reduced.
It can damage the various electronic parts to shorten the service life of the device, and also cause a lot of inconvenience due to the noise generated if the door is closing with high speed when it enters door closing stage due to this disadvantage.
In the meantime, for example, Korean Patent Publication No. KR10-2010-0055110A, titled “door hinge” is an invention to solve above mentioned drawbacks.
In the above patent publication, a damper is attached to a door hinge to damp the closing speed of the door.
In the KR 10-2010-0055110A, the closing speed of the door is dampened by mounting a damper to the door hinge.
However, the above patent publication, the damper may continuously resist the door frame mounted on the door in a process of directly hitting the damper and attenuates the closing speed of the door.
Thus, such a structure has a problem that unnecessary maintenance is required because the damper cannot withstand the impact but often be broken due to repetitive uses for a certain period of time.